Perylene derivative synthesis process, perylene derivative and organic EL device

ABSTRACT

The invention aims to provide a perylene derivative preparation process featuring satisfactory yields and improved preparation efficiency, a perylene derivative obtained by the process, and an organic EL device using the same.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] This invention relates to an organic electro-luminescent (EL)device, and more particularly, to a compound for use in a device of thetype wherein an electric field is applied across a thin film of anorganic compound to emit light.

[0003] 2. Background Art

[0004] Organic electroluminescent (EL) devices include a thin filmcontaining a luminescent organic compound interleaved between anelectron injecting electrode and a hole injecting electrode. Electronsand holes are injected into the thin film where they are recombined tocreate excitons. Light is emitted by utilizing luminescence(phosphorescence or fluorescence) upon deactivation of excitons.

[0005] The organic EL devices are characterized by plane light emissionat a high luminance of about 100 plus to about 10,000 plus cd/m² with avoltage of about 10 volts and light emission in a spectrum from blue tored color by a simple choice of the type of fluorescent material.

[0006] Doping is one technique for producing light emission of anydesired color from organic EL devices. It was reported in Jpn. J. Appl.Phys., 10, 527 (1971) to change emission color from blue to green bydoping anthracene crystals with a minor level of tetracene. With respectto organic thin film EL devices having a multilayer structure, it wasreported in JP-A 63-264692 to incorporate in a host material having alight emitting function a minor amount of a fluorescent dye capable ofemitting light different from that of the host material in response tolight emission from the host material as a dopant to form a lightemitting layer, thereby changing the color of light emission from greento orange or red.

[0007] With respect to long wavelength light emission of yellow to red,known light emitting materials or dopant materials include laser dyescapable of red oscillation (EPO 281381), compounds capable of exciplexemission (JP-A 2-255788), coumarin compounds (JP-A 3-792),dicyano-methylene compounds (JP-A 3-162481), thioxanthene compounds(JP-A 3-177486), mixtures of a conjugated polymer and an electrontransporting compound (JP-A 6-73374), squalirium compounds (JP-A6-93257), oxadiazole compounds (JP-A 6-136359), oxynate derivatives(JP-A 6-145146), and pyrene compounds (JP-A 6-240246).

[0008] It is reported in J. Am. Chem. Soc., 118, 2374-2379, 1996, thatbenzofluoranthene derivatives have a very high fluorescent quantumyield. JP-A 10-330295 and JP-A 11-233261 disclose organic EL deviceshaving a light emitting layer in which a variety of host materials aredoped with dibenzo[f,f′]diindeno[1,2,3-cd:1′,2′,3′-lm]perylenederivatives derived from benzofluoranthene.

[0009] For the synthesis of perylene derivatives encompassing suchbenzofluoranthene derivatives, it is a common practice to conductsynthesis using starting reactants of the following formulae (A), (B)and (C) and catalysts.

[0010] However, these prior art synthesis procedures suffer from theproblem of very low efficiency because the end products are obtained inyields of at most 20%. Although the prior art synthesis procedures arerelatively easy to synthesize an end product having symmetry, theyencounter a problem when it is desired to obtain an end product havingno symmetry. That is, since it is difficult to directly synthesize theasymmetric end product, the asymmetric end product must be separatedfrom a variety of reaction products, which indicates a very lowpreparation efficiency and restricts the degree of freedom of compounddesign.

SUMMARY OF THE INVENTION

[0011] An object of the invention is to provide a perylene derivativesynthesis process featuring a satisfactory yield and improvedpreparation efficiency, a perylene derivative obtained by the process,and an organic EL device using the same.

[0012] The above objects are achieved by the construction which isdefined below as [1] to [22].

[0013] [1] A process for synthesizing a perylene derivative comprisingthe steps of halogenating a reactant and subjecting the halogenatedreactant at its halogenated site to coupling reaction or the steps ofusing a halogenated reactant and a boronized reactant and subjectingthem at their halogenated and boronized sites to Suzuki couplingreaction, or combining the foregoing steps.

[0014] [2] A process for synthesizing a perylene derivative according to[1] wherein

[0015] a 1,8-dihalogenated naphthalene derivative of the followingformula (1):

[0016] wherein X is Cl, Br or I, R₁ to R₄, R₁₁ and R₁₂ each are ahydrogen atom, a straight, branched or cyclic alkyl radical which may besubstituted, a straight, branched or cyclic alkoxy radical which may besubstituted, a straight, branched or cyclic alkylthio radical which maybe substituted, a straight, branched or cyclic alkenyl radical which maybe substituted, a straight, branched or cyclic alkenyloxy radical whichmay be substituted, a straight, branched or cyclic alkenylthio radicalwhich may be substituted, a substituted or unsubstituted aralkylradical, a substituted or unsubstituted aralkyloxy radical, asubstituted or unsubstituted aralkylthio radical, a substituted orunsubstituted aryl radical, a substituted or unsubstituted aryloxyradical, a substituted or unsubstituted arylthio radical, a substitutedor unsubstituted amino radical, a cyano radical, a hydroxyl radical, a—COOM₁ radical (wherein M₁ is a hydrogen atom, a straight, branched orcyclic alkyl radical which may be substituted, a straight, branched orcyclic alkenyl radical which may be substituted, a substituted orunsubstituted aralkyl radical, or a substituted or unsubstituted arylradical), a —COM₂ radical (wherein M₂ is a hydrogen atom, a straight,branched or cyclic alkyl radical which may be substituted, a straight,branched or cyclic alkenyl radical which may be substituted, asubstituted or unsubstituted aralkyl radical, a substituted orunsubstituted aryl radical, or an amino radical), or a —OCOM₃ radical(wherein M₃ is a straight, branched or cyclic alkyl radical which may besubstituted, a straight, branched or cyclic alkenyl radical which may besubstituted, a substituted or unsubstituted aralkyl radical, or asubstituted or unsubstituted aryl radical), and at least two adjoiningradicals selected from among R₁ to R₄, R₁₁ and R₁₂ may bond or fusetogether to form a substituted or unsubstituted carbocyclic aliphaticring, aromatic ring or fused aromatic ring with the carbon atoms onwhich they substitute, with the proviso that when the carbocyclicaliphatic ring, aromatic ring or fused aromatic ring has substituentradicals, the substituent radicals are the same as R₁ to R₄, R₁₁ andR₁₂,

[0017] is subjected to coupling reaction to synthesize a perylenederivative of the following formula (2):

[0018] wherein R₁′, to R₄′, R₁₁′ and R₁₂′ are as defined for R₁ to R₄,R₁₁ and R₁₂ in formula (1), and R₁ to R₄, R₁₁ and R₁₂ and R₁′ to R₄′,R₁₁′ and R₁₂′ may be the same or different.

[0019] [3] A process for synthesizing a perylene derivative according to[1] wherein

[0020] a 3,4-dihalogenated fluoranthene derivative of the followingformula (3):

[0021] wherein X is Cl, Br or I, R₁ to R₆, R₂₁ and R₂₂ each are ahydrogen atom, a straight, branched or cyclic alkyl radical which may besubstituted, a straight, branched or cyclic alkoxy radical which may besubstituted, a straight, branched or cyclic alkylthio radical which maybe substituted, a straight, branched or cyclic alkenyl radical which maybe substituted, a straight, branched or cyclic alkenyloxy radical whichmay be substituted, a straight, branched or cyclic alkenylthio radicalwhich may be substituted, a substituted or unsubstituted aralkylradical, a substituted or unsubstituted aralkyloxy radical, asubstituted or unsubstituted aralkylthio radical, a substituted orunsubstituted aryl radical, a substituted or unsubstituted aryloxyradical, a substituted or unsubstituted arylthio radical, a substitutedor unsubstituted amino radical, a cyano radical, a hydroxyl radical, a—COOM₁ radical (wherein M₁ is a hydrogen atom, a straight, branched orcyclic alkyl radical which may be substituted, a straight, branched orcyclic alkenyl radical which may be substituted, a substituted orunsubstituted aralkyl radical, or a substituted or unsubstituted arylradical), a —COM₂ radical (wherein M₂ is a hydrogen atom, a straight,branched or cyclic alkyl radical which may be substituted, a straight,branched or cyclic alkenyl radical which may be substituted, asubstituted or unsubstituted aralkyl radical, a substituted orunsubstituted aryl radical, or an amino radical), or a —OCOM₃ radical(wherein M₃ is a straight, branched or cyclic alkyl radical which may besubstituted, a straight, branched or cyclic alkenyl radical which may besubstituted, a substituted or unsubstituted aralkyl radical, or asubstituted or unsubstituted aryl radical), and at least two adjoiningradicals selected from among R₁ to R₆, R₂₁ and R₂₂ may bond or fusetogether to form a substituted or unsubstituted carbocyclic aliphaticring, aromatic ring or fused aromatic ring with the carbon atoms onwhich they substitute, is subjected to coupling reaction to synthesize aperylene derivative of the following formula (4):

[0022] wherein R₁′ to R₆′, R₂₁′ and R₂₂′ are as defined for R₁ to R₆,R₂₁ and R₂₂ in formula (3), and R₁ to R₆, R₂₁ and R₂₂ and R₁′ to R₆′,R₂₁′ and R₂₂′ may be the same or different.

[0023] [4] A process for synthesizing a perylene derivative according to[1] wherein

[0024] a 3,4-dihalogenated benzofluoranthene derivative of the followingformula (5):

[0025] wherein X is Cl, Br or I, R₁ to R₈, R₃₁ and R₃₂ each are ahydrogen atom, a straight, branched or cyclic alkyl radical which may besubstituted, a straight, branched or cyclic alkoxy radical which may besubstituted, a straight, branched or cyclic alkylthio radical which maybe substituted, a straight, branched or cyclic alkenyl radical which maybe substituted, a straight, branched or cyclic alkenyloxy radical whichmay be substituted, a straight, branched or cyclic alkenylthio radicalwhich may be substituted, a substituted or unsubstituted aralkylradical, a substituted or unsubstituted aralkyloxy radical, asubstituted or unsubstituted aralkylthio radical, a substituted orunsubstituted aryl radical, a substituted or unsubstituted aryloxyradical, a substituted or unsubstituted arylthio radical, a substitutedor unsubstituted amino radical, a cyano radical, a hydroxyl radical, a—COOM₁ radical (wherein M₁ is a hydrogen atom, a straight, branched orcyclic alkyl radical which may be substituted, a straight, branched orcyclic alkenyl radical which may be substituted, a substituted orunsubstituted aralkyl radical, or a substituted or unsubstituted arylradical), a —COM₂ radical (wherein M₂ is a hydrogen atom, a straight,branched or cyclic alkyl radical which may be substituted, a straight,branched or cyclic alkenyl radical which may be substituted, asubstituted or unsubstituted aralkyl radical, a substituted orunsubstituted aryl radical, or an amino radical), or a —OCOM₃ radical(wherein M₃ is a straight, branched or cyclic alkyl radical which may besubstituted, a straight, branched or cyclic alkenyl radical which may besubstituted, a substituted or unsubstituted aralkyl radical, or asubstituted or unsubstituted aryl radical), and at least two adjoiningradicals selected from among R₁ to R₈, R₃₁ and R₃₂ may bond or fusetogether to form a substituted or unsubstituted carbocyclic aliphaticring, aromatic ring or fused aromatic ring with the carbon atoms onwhich they substitute, is subjected to coupling reaction to synthesize aperylene derivative of the following formula (6):

[0026] wherein R₁′ to R₈′, R₃₁′ and R₃₂′ are as defined for R₁ to R₈,R₃₁ and R₃₂ in formula (5), and R₁ to R₈, R₃₁ and R₃₂ and R₁′ to R₈′,R₃₁′ and R₃₂′ may be the same or different.

[0027] [5] A process for synthesizing a perylene derivative according toany one of [1] to [4] wherein the coupling reaction is homo- orhetero-coupling reaction using a catalyst.

[0028] [6] A process for synthesizing a perylene derivative according to[5] wherein the catalyst is a metal catalyst, metal complex catalyst ormetal compound (exclusive of metallic copper) containing at least oneelement selected from among the Group VIII elements of Ni, Pd, Pt, Fe,Co, Ru and Rh, and the Group IB elements.

[0029] [7] A process for synthesizing a perylene derivative according to[5] or [6] wherein said catalyst is NiCl₂(dppe), NiCl₂(dppp) orNi(COD)₂.

[0030] [8] A process for synthesizing a perylene derivative according to[1], including the steps of using a 1,8-dihalogenated naphthalenederivative of formula (1) as set forth in above [2] and anaphthyl-1,8-diboronic acid derivative of the following formula (7):

[0031] wherein Z is a boronic acid derivative, and R₁ to R₄, R₁₁ and R₁₂are as defined in formula (1), and subjecting them to Suzuki couplingreaction, thereby synthesizing a perylene derivative of formula (2).

[0032] [9] A process for synthesizing a perylene derivative according to[1], including the steps of using a 3,4-dihalogenated fluoranthenederivative of formula (3) as set forth in above [3] and afluorantheno-1,8-diboronic acid derivative of the following formula (8):

[0033] wherein Z is a boronic acid derivative, and R₁ to R₆, R₂₁ and R₂₂are as defined in formula (3), and subjecting them to Suzuki couplingreaction, thereby synthesizing a perylene derivative of formula (4).

[0034] [10] A process for synthesizing a perylene derivative accordingto [1], including the steps of using a 3,4-dihalogenatedbenzofluoranthene derivative of formula (5) as set forth in above [4]and a dibenzofluorantheno-1,8-diboronic acid derivative of the followingformula (9):

[0035] wherein Z is a boronic acid derivative, and R₁ to R₈, R₃₁ and R₃₂are as defined in formula (5), and subjecting them to Suzuki couplingreaction, thereby synthesizing a perylene derivative of formula (6).

[0036] [11] A process for synthesizing a perylene derivative accordingto [1], including the steps of using a naphthalene derivative of thefollowing formula (13):

[0037] wherein X is Cl, Br or I, Z is a boronic acid derivative, and R₁to R₄, R₁₁ and R₁₂ are as defined in formula (1), and subjecting it toSuzuki coupling reaction, thereby synthesizing a perylene derivative.

[0038] [12] A perylene derivative synthesizing process comprising thesteps of using a fluoranthene derivative of the following formula (14):

[0039] wherein X is Cl, Br or I, Z is a boronic acid derivative, and R₁to R₆, R₂₁ and R₂₂ are as defined in formula (3), and subjecting it toSuzuki coupling reaction, thereby synthesizing a perylene derivative.

[0040] [13] A perylene derivative synthesizing process comprising thesteps of using a benzofluoranthene derivative of the following formula(15):

[0041] wherein X is Cl, Br or I, Z is a boronic acid derivative, and R₁to R₈, R₃₁ and R₃₂ are as defined in formula (5), and subjecting it toSuzuki coupling reaction, thereby synthesizing a perylene derivative.

[0042] [14] A perylene derivative synthesizing process wherein at leastone derivative selected from among 1,8-dihalogenated naphthalenederivatives of formula (1), 3,4-dihalogenated fluoranthene derivativesof formula (3), and 3,4-dihalogenated benzofluoranthene derivatives offormula (5) as set forth in [2] to [4] is used to form an asymmetriccompound.

[0043] [15] A perylene derivative synthesizing process according to [14]wherein the asymmetric compound is a compound of the following formula(10):

[0044] wherein R₅₁ to R₅₅, R₆₁ to R₆₅, R₁₁₁ and R₁₂₁ are as defined forR₁ to R₄, R₁₁ and R₁₂ in formula (1).

[0045] [16] A perylene derivative synthesizing process according to [1]wherein the perylene derivative is a compound of the following formula(11):

[0046] wherein R₁₁₁, R₁₂₁, R₁₁₁′ and R₁₂₁′ are as defined for R₁ to R₄,R₁₁, and R₁₂ in formula (1).

[0047] [17] A perylene derivative synthesizing process according to [1]wherein said perylene derivative is a compound of the following formula(12):

[0048] wherein R₁₁₁, R₁₂₁, R₁₁₁′ and R₁₂₁′ are as defined for R₁ to R₄,R₁₁ and R₁₂ in formula (1).

[0049] [18] A perylene derivative synthesizing process according to anyone of [4] to [7] wherein at least R₅ and R₆ and/or R₅′ and R₆′ aredifferent.

[0050] [19] A process for synthesizing a perylene derivative accordingto [1] wherein

[0051] a bisnaphthalene derivative of the following formula (16):

[0052] wherein X is Cl, Br or I, R₁ to R₄, R₁₁ and R₁₂ each are ahydrogen atom, a straight, branched or cyclic alkyl radical which may besubstituted, a straight, branched or cyclic alkoxy radical which may besubstituted, a straight, branched or cyclic alkylthio radical which maybe substituted, a straight, branched or cyclic alkenyl radical which maybe substituted, a straight, branched or cyclic alkenyloxy radical whichmay be substituted, a straight, branched or cyclic alkenylthio radicalwhich may be substituted, a substituted or unsubstituted aralkylradical, a substituted or unsubstituted aralkyloxy radical, asubstituted or unsubstituted aralkylthio radical, a substituted orunsubstituted aryl radical, a substituted or unsubstituted aryloxyradical, a substituted or unsubstituted arylthio radical, a substitutedor unsubstituted amino radical, a cyano radical, a hydroxyl radical, a—COOM₁ radical (wherein M₁ is a hydrogen atom, a straight, branched orcyclic alkyl radical which may be substituted, a straight, branched orcyclic alkenyl radical which may be substituted, a substituted orunsubstituted aralkyl radical, or a substituted or unsubstituted arylradical), a —COM₂ radical (wherein M₂ is a hydrogen atom, a straight,branched or cyclic alkyl radical which may be substituted, a straight,branched or cyclic alkenyl radical which may be substituted, asubstituted or unsubstituted aralkyl radical, a substituted orunsubstituted aryl radical, or an amino radical), or a —OCOM₃ radical(wherein M₃ is a straight, branched or cyclic alkyl radical which may besubstituted, a straight, branched or cyclic alkenyl radical which may besubstituted, a substituted or unsubstituted aralkyl radical, or asubstituted or unsubstituted aryl radical), and at least two adjoiningradicals selected from among R₁ to R₄, R₁₁ and R₁₂ may bond or fusetogether to form a substituted or unsubstituted carbocyclic aliphaticring, aromatic ring or fused aromatic ring with the carbon atoms onwhich they substitute, with the proviso that when the carbocyclicaliphatic ring, aromatic ring or fused aromatic ring has substituentradicals, the substituent radicals are the same as R₁ to R₄, R₁₁ andR₁₂,

[0053] is subjected to coupling reaction to synthesize a perylenederivative of the following formula (2):

[0054] wherein R₁′ to R₄′, R₁₁′ and R₁₂′ are as defined for R₁ to R₄,R₁₁ and R₁₂ in formula (1), and R₁ to R₄, R₁₁ and R₁₂ and R₁′ to R₄′,R₁₁′ and R₁₂′ may be the same or different.

[0055] [20] An organic EL device comprising the perylene derivativeobtained by the process of any one of [1] to [19].

[0056] [21] An organic EL device according to [20] wherein the perylenederivative is contained in a light emitting layer.

[0057] [22] A perylene derivative having a structure of the followingformula (10):

[0058] wherein R₅₁ to R₅₅, R₆₁ to R₆₅, R₁₁₁ and R₁₂₁ are as defined forR₁ to R₄, R₁₁ and R₁₂ in formula (1).

BRIEF DESCRIPTION OF THE DRAWING

[0059]FIG. 1 is a schematic cross-sectional view showing the basicconstruction of an organic EL device according to the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0060] The synthesis process of the invention is to produce a perylenederivative by halogenating a starting reactant and subjecting thehalogenated reactant to coupling reaction or using a halogenatedreactant and a boronized reactant and subjecting them to Suzuki couplingreaction, or combining the foregoing routes.

[0061] By these synthesis processes, the desired perylene derivativescan be quite efficiently synthesized and their yield can reach 90% orhigher. Even asymmetric end products can be synthesized in a relativelysimple manner by either of the synthesis processes or a combinationthereof, indicating a spreading of the use and application of asymmetriccompounds which found little use in the prior art.

[0062] Now the respective embodiments of the inventive synthesis processare described in detail. First Embodiment: Halogenation followed bycoupling

[0063] The first embodiment of the inventive synthesis process involveshalogenating a 1,8-dihalogenated naphthalene derivative of the followingformula (1), and subjecting it to coupling reaction for therebysynthesizing a perylene derivative of the following formula (2).

[0064] Referring to formula (1), R₁ to R₄, R₁₁ and R₁₂ each are ahydrogen atom, a straight, branched or cyclic alkyl radical which may besubstituted, a straight, branched or cyclic alkoxy radical which may besubstituted, a straight, branched or cyclic alkylthio radical which maybe substituted, a straight, branched or cyclic alkenyl radical which maybe substituted, a straight, branched or cyclic alkenyloxy radical whichmay be substituted, a straight, branched or cyclic alkenylthio radicalwhich may be substituted, a substituted or unsubstituted aralkylradical, a substituted or unsubstituted aralkyloxy radical, asubstituted or unsubstituted aralkylthio radical, a substituted orunsubstituted aryl radical, a substituted or unsubstituted aryloxyradical, a substituted or unsubstituted arylthio radical, a substitutedor unsubstituted amino radical, a cyano radical, a hydroxyl radical, a—COOM₁ radical (wherein M₁ is a hydrogen atom, a straight, branched orcyclic alkyl radical which may be substituted, a straight, branched orcyclic alkenyl radical which may be substituted, a substituted orunsubstituted aralkyl radical, or a substituted or unsubstituted arylradical), a —COM₂ radical (wherein M₂ is a hydrogen atom, a straight,branched or cyclic alkyl radical which may be substituted, a straight,branched or cyclic alkenyl radical which may be substituted, asubstituted or unsubstituted aralkyl radical, a substituted orunsubstituted aryl radical, or an amino radical), or a —OCOM₃ radical(wherein M₃ is a straight, branched or cyclic alkyl radical which may besubstituted, a straight, branched or cyclic alkenyl radical which may besubstituted, a substituted or unsubstituted aralkyl radical, or asubstituted or unsubstituted aryl radical), and at least two adjoiningradicals selected from among R₁ to R₄, R₁₁ and R₁₂ may bond or fusetogether to form a substituted or unsubstituted carbocyclic aliphaticring, aromatic ring or fused aromatic ring with the carbon atoms onwhich they substitute, with the proviso that when the carbocyclicaliphatic ring, aromatic ring or fused aromatic ring has substituentradicals, the substituent radicals are the same as R₁ to R₄, R₁₁ andR₁₂.

[0065] As used herein, the term “aryl radical” represents carbocyclicaromatic radicals such as phenyl and naphthyl and heterocyclic aromaticradicals such as furyl, thienyl and pyridyl.

[0066] In formula (1), when R₁ to R₄, R₁₁ and R₁₂ stand for straight,branched or cyclic alkyl radicals, straight, branched or cyclic alkoxyradicals, straight, branched or cyclic alkylthio radicals, straight,branched or cyclic alkenyl radicals, straight, branched or cyclicalkenyloxy radicals, and straight, branched or cyclic alkenylthioradicals, these radicals may have substituent radicals. For example,they may be mono- or multi-substituted with halogen atoms, aryl radicalsof 4 to 20 carbon atoms, alkoxy radicals of 1 to 20 carbon atoms,alkoxyalkoxy radicals of 2 to 20 carbon atoms, alkenyloxy radicals of 2to 20 carbon atoms, aralkyloxy radicals of 4 to 20 carbon atoms,aralkyloxyalkoxy radicals of 5 to 20 carbon atoms, aryloxy radicals of 3to 20 carbon atoms, aryloxyalkoxy radicals of 4 to 20 carbon atoms,arylalkenyl radicals 5 to 20 carbon atoms, aralkylalkenyl radicals of 6to 20 carbon atoms, alkylthio radicals of 1 to 20 carbon atoms,alkoxyalkylthio radicals of 2 to 20 carbon atoms, alkylthioalkylthioradicals of 2 to 20 carbon atoms, alkenylthio radicals of 2 to 20 carbonatoms, aralkylthio radicals of 4 to 20 carbon atoms, aralkyloxyalkylthioradicals of 5 to 20 carbon atoms, aralkylthioalkylthio radicals of 5 to20 carbon atoms, arylthio radicals of 3 to 20 carbon atoms,aryloxyalkylthio radicals of 4 to 20 carbon atoms, arylthioalkylthioradicals of 4 to 20 carbon atoms, heteroatom-containing cyclic alkylradicals of 4 to 20 carbon atoms, and halogen atoms. The aryl radicalsin these substituent radicals may have further substituted thereon alkylradicals of 1 to 10 carbon atoms, alkoxy radicals of 1 to 10 carbonatoms, aryl radicals of 3 to 10 carbon atoms, aralkyl radicals of 4 to10 carbon atoms or the like.

[0067] In formula (1), when R₁ to R₄, R₁₁ and R₁₂ stand for aralkyl,aralkyloxy, aralkylthio, aryl, aryloxy and arylthio radicals, the arylradicals in these radicals may have substituent radicals. For example,they may be mono- or multi-substituted with alkyl radicals of 1 to 20carbon atoms, alkenyl radicals of 2 to 20 carbon atoms, aralkyl radicalsof 4 to 20 carbon atoms, aryl radicals of 3 to 20 carbon atoms, alkoxyradicals of 1 to 20 carbon atoms, alkoxyalkyl radicals of 2 to 20 carbonatoms, alkoxyalkyloxy radicals of 2 to 20 carbon atoms, alkenyloxyradicals of 2 to 20 carbon atoms, alkenyloxyalkyl radicals of 3 to 20carbon atoms, alkenyloxyalkyloxy radicals of 3 to 20 carbon atoms,aralkyloxy radicals of 4 to 20 carbon atoms, aralkyloxyalkyl radicals of5 to 20 carbon atoms, aralkyloxyalkyloxy radicals of 5 to 20 carbonatoms, aryloxy radicals of 3 to 20 carbon atoms, aryloxyalkyl radicalsof 4 to 20 carbon atoms, aryloxyalkyloxy radicals of 4 to 20 carbonatoms, alkylcarbonyl radicals of 2 to 20 carbon atoms, alkenylcarbonylradicals of 3 to 20 carbon atoms, aralkylcarbonyl radicals of 5 to 20carbon atoms, arylcarbonyl radicals of 4 to 20 carbon atoms,alkoxycarbonyl radicals of 2 to 20 carbon atoms, alkenyloxycarbonylradicals of 3 to 20 carbon atoms, aralkyloxycarbonyl radicals of 5 to 20carbon atoms, aryloxycarbonyl radicals of 4 to 20 carbon atoms,alkylcarbonyloxy radicals of 2 to 20 carbon atoms, alkenylcarbonyloxyradicals of 3 to 20 carbon atoms, aralkylcarbonyloxy radicals of 5 to 20carbon atoms, arylcarbonyloxy radicals of 4 to 20 carbon atoms,alkylthio radicals of 1 to 20 carbon atoms, aralkylthio radicals of 4 to20 carbon atoms, arylthio radicals of 3 to 20 carbon atoms, nitroradicals, cyano radicals, formyl radicals, halogen atoms, halogenatedalkyl radicals, hydroxyl radicals, amino radicals, N-mono-substitutedamino radicals of 1 to 20 carbon atoms, and N,N-di-substituted aminoradicals of 2 to 40 carbon atoms.

[0068] The aryl radicals in these substituent radicals may have furthersubstituted thereon alkyl radicals of 1 to 10 carbon atoms, alkoxyradicals of 1 to 10 carbon atoms, aryl radicals of 6 to 10 carbon atoms,aralkyl radicals of 7 to 10 carbon atoms or the like.

[0069] In formula (1), the amino radicals represented by R₁ to R₄, R₁₁and R₁₂ may have substituent radicals. For example, they may be mono- ordi-substituted with alkyl radicals of 1 to 20 carbon atoms, aralkylradicals of 4 to 20 carbon atoms, or aryl radicals of 3 to 20 carbonatoms.

[0070] Further, two adjoining radicals selected from among R₁ to R₄, R₁₁and R₁₂ may bond or fuse together to form a substituted or unsubstitutedcarbocyclic aliphatic ring, aromatic ring or fused aromatic ring withthe carbon atoms on which they substitute.

[0071] The naphthalene derivative of formula (1) is halogenated withhalogen atoms X which are bonded at the 1, 8 positions thereof. Thehalogen atoms X used for halogenation may be Cl, Br or I, with Br beingespecially preferred. Two halogen atoms X may be the same or differentalthough they are often the same.

[0072] After the compound of formula (1) is modified with halogen atoms,it is subjected to coupling reaction. The coupling reaction may beconducted by various well-known techniques although the presentinvention favors a technique of conducting homo- or hetero-couplingreaction using a catalyst.

[0073] The catalyst used in the reaction is not critical as long as itcan promote the coupling reaction, and various catalysts may be used.Examples of the catalyst include metal catalysts, metal complexcatalysts and metal compounds containing one or more elements selectedfrom among the Group VIII elements of Ni, Pd, Pt, Fe, Co, Ru, Rh, etc.and the Group IB elements. Alternatively, use may also be made of metalcomplex catalysts and metal compounds of Cu.

[0074] Of these, nickel catalysts are preferred. Nickel catalysts invarious forms may be used. Examples of suitable nickel catalysts include[1,2-bis(diphenyl-phosphino)ethane]dichloronickel (II), referred to asNiCl₂(dppe), [1,3-bis(diphenylphosphino)propane]-dichloronickel (II),referred to as NiCl₂(dppp), tetrakis(triphenylphosphine)nickel, andnickel-bis-(1,5-cyclooctadiene), referred to as Ni(COD)₂. In thisregard, the use of NiCl₂(dppe) or NiCl₂(dppp) brings about Grignardcoupling.

[0075] Coupling reaction conditions differ with a particular reactantand catalyst. In one exemplary reaction using Ni(COD)₂, a halogenatednaphthalene derivative is dissolved in a solvent such as DMF, in aconcentration of about 0.01 to 10 mol/l, especially about 0.05 to 1mol/l, with which the nickel catalyst (Ni(COD)₂ etc.) is admixed. Theamount of the catalyst used is usually an equimolar amount, but theamount preferred in consideration of the probable event where part ofthe catalyst loses activity is in the range from equimolar to 1.5 times,and especially equimolar to 1.2 times on a molar basis. Also, ifnecessary, cyclooctadiene (COD) is added in an amount of 2 to 10 molesper mole of the halogenated naphthalene, and bipyridine is added in anamount of 0.5 to 5 moles per mole of the halogenated derivative. Undersuch conditions, reaction is effected at a temperature of 50 to 100° C.,especially 60 to 90° C. for about 0.5 to 12 hours, especially about 1 to5 hours. At the end of reaction, aqueous hydrochloric acid, methanol orthe like is added whereby the end compound is precipitated for recovery.

[0076] Through coupling reaction on the halogenated naphthalene,preferably in the presence of the catalyst, a compound of formula (2) isproduced.

[0077] In formula (2), R₁′ to R₄′, R₁₁′ and R₁₂′ are as defined for R₁to R₄, R₁₁ and R₁₂ in formula (1). R₁ to R₄, R₁₁ and R₁₂ and R₁′ to R₄′,R₁₁′ and R₁₂′ may be the same or different, and preferably different.

[0078] In accordance with the first embodiment of the inventioninvolving coupling reaction on the halogenated naphthalene, preferablyin the presence of the catalyst, it is possible to synthesize a perylenederivative of the following formula (4) by subjecting a3,4-dihalogenated fluoranthene derivative of the following formula (3)to coupling reaction.

[0079] In formula (3), R₁ to R₆, R₂₁ and R₂₂ have the same meaning as R₁to R₄, R₁₁ and R₁₂ in formula (1), and their preferred range is also thesame.

[0080] Namely, R₁ to R₆, R₂₁ and R₂₂ in formula (3) each are a hydrogenatom, a straight, branched or cyclic alkyl radical which may besubstituted, a straight, branched or cyclic alkoxy radical which may besubstituted, a straight, branched or cyclic alkylthio radical which maybe substituted, a straight, branched or cyclic alkenyl radical which maybe substituted, a straight, branched or cyclic alkenyloxy radical whichmay be substituted, a straight, branched or cyclic alkenylthio radicalwhich may be substituted, a substituted or unsubstituted aralkylradical, a substituted or unsubstituted aralkyloxy radical, asubstituted or unsubstituted aralkylthio radical, a substituted orunsubstituted aryl radical, a substituted or unsubstituted aryloxyradical, a substituted or unsubstituted arylthio radical, a substitutedor unsubstituted amino radical, a cyano radical, a hydroxyl radical, a—COOM₁ radical (wherein M₁ is a hydrogen atom, a straight, branched orcyclic alkyl radical which may be substituted, a straight, branched orcyclic alkenyl radical which may be substituted, a substituted orunsubstituted aralkyl radical, or a substituted or unsubstituted arylradical), a —COM₂ radical (wherein M₂ is a hydrogen atom, a straight,branched or cyclic alkyl radical which may be substituted, a straight,branched or cyclic alkenyl radical which may be substituted, asubstituted or unsubstituted aralkyl radical, a substituted orunsubstituted aryl radical, or an amino radical), or a —OCOM₃ radical(wherein M₃ is a straight, branched or cyclic alkyl radical which may besubstituted, a straight, branched or cyclic alkenyl radical which may besubstituted, a substituted or unsubstituted aralkyl radical, or asubstituted or unsubstituted aryl radical), and at least two adjoiningradicals selected from among R₁ to R₆, R₂₁ and R₂₂ may bond or fusetogether to form a substituted or unsubstituted carbocyclic aliphaticring, aromatic ring or fused aromatic ring with the carbon atoms onwhich they substitute.

[0081] In formula (4), R₁′ to R₆′, R₂₁′ and R₂₂′ are as defined for R₁to R₆, R₂₁ and R₂₂ in formula (3). R₁ to R₆, R₂₁ and R₂₂ and R₁′ to R₆′,R₂₁′ and R₂₂′ may be the same or different.

[0082] In accordance with the first embodiment of the inventioninvolving coupling reaction on the halogenated naphthalene, preferablyin the presence of the catalyst, it is possible to synthesize a perylenederivative of the following formula (6) by subjecting a3,4-dihalogenated benzofluoranthene derivative of the following formula(5) to coupling reaction.

[0083] In formula (5), R₁ to R₈, R₃₁ and R₃₂ have the same meaning as R₁to R₄, R₁₁ and R₁₂ in formula (1), and their preferred range is also thesame.

[0084] Namely, R₁ to R₈, R₃₁ and R₃₂ in formula (5) each are a hydrogenatom, a straight, branched or cyclic alkyl radical which may besubstituted, a straight, branched or cyclic alkoxy radical which may besubstituted, a straight, branched or cyclic alkylthio radical which maybe substituted, a straight, branched or cyclic alkenyl radical which maybe substituted, a straight, branched or cyclic alkenyloxy radical whichmay be substituted, a straight, branched or cyclic alkenylthio radicalwhich may be substituted, a substituted or unsubstituted aralkylradical, a substituted or unsubstituted aralkyloxy radical, asubstituted or unsubstituted aralkylthio radical, a substituted orunsubstituted aryl radical, a substituted or unsubstituted aryloxyradical, a substituted or unsubstituted arylthio radical, a substitutedor unsubstituted amino radical, a cyano radical, a hydroxyl radical, a—COOM₁ radical (wherein M₁ is a hydrogen atom, a straight, branched orcyclic alkyl radical which may be substituted, a straight, branched orcyclic alkenyl radical which may be substituted, a substituted orunsubstituted aralkyl radical, or a substituted or unsubstituted arylradical), a —COM₂ radical (wherein M₂ is a hydrogen atom, a straight,branched or cyclic alkyl radical which may be substituted, a straight,branched or cyclic alkenyl radical which may be substituted, asubstituted or unsubstituted aralkyl radical, a substituted orunsubstituted aryl radical, or an amino radical), or a —OCOM₃ radical(wherein M₃ is a straight, branched or cyclic alkyl radical which may besubstituted, a straight, branched or cyclic alkenyl radical which may besubstituted, a substituted or unsubstituted aralkyl radical, or asubstituted or unsubstituted aryl radical), and at least two adjoiningradicals selected from among R₁ to R₈, R₃₁ and R₃₂ may bond or fusetogether to form a substituted or unsubstituted carbocyclic aliphaticring, aromatic ring or fused aromatic ring with the carbon atoms onwhich they substitute.

[0085] In formula (6), R₁′ to R₈′, R₃₁′ and R₃₂′ are as defined for R₁to R₈, R₃₁ and R₃₂ in formula (5). R₁ to R₈, R₃₁ and R₃₂ and R₁′ to R₈′,R₃₁′ and R₃₂′ may be the same or different.

[0086] It is preferred that at least R₅ and R₆ and/or R₅′ and R₆′ informula (6) be different. The provision of such an asymmetric structurecan yield materials capable of emitting orange to red light when used asthe organic EL material, and electron or hole transporting materials.

[0087] Also the asymmetric structure can improve solubility which makesmaterial purification easy, retard decomposition upon sublimationpurification, and improve fluorescence. The asymmetric structure canfurther reduce the interaction between similar or distinct molecules,improve the fluorescent luminance of EL devices, and suppress theconcentration quenching which increases the margin as the EL dopant andimproves the freedom of design.

[0088] Moreover, an asymmetric compound can be obtained by using one ormore derivatives selected from among 1,8-dihalogenated naphthalenederivatives of formula (1), 3,4-dihalogenated fluoranthene derivativesof formula (3), and 3,4-dihalogenated benzofluoranthene derivatives offormula (5) and effecting hetero-coupling reaction.

[0089] In this way, asymmetric compounds can be readily and freelyproduced using the inventive process, while the yield of the desiredcompounds is dramatically increased.

[0090] These asymmetric compounds are not critical as long as they areobtainable from a combination of formulae (1), (3) and (5). Inparticular, compounds of the following formula (10) are preferred in thepractice of the invention.

[0091] In formula (10), R₅₁ to R₅₅, R₆₁ to R₆₅, R₁₁₁′ and R₁₂₁′ are asdefined for R₁ to R₄, R₁₁ and R₁₂ in formula (1). Also, R₁ to R₄, R₁′ toR₄′, R₃₁ and R₃₂ are as defined in formula (1).

[0092] The provision of such a structure can yield materials capable ofemitting orange to green light when used as the organic EL material, andelectron or hole transporting materials.

[0093] It is further preferred that the perylene derivative of formula(2) be a compound of the following formula (11).

[0094] In formula (11), R₁₁₁, R₁₂₁, R₁₁₁′ and R₁₂₁′ are as defined forR₁ to R₄, R₁₁ and R₁₂ in formula (1).

[0095] Alternatively, the perylene derivative of formula (2) may be acompound of the following formula (12).

[0096] In formula (12), R₁₁₁, R₁₂₁, R₁₁₁′ and R₁₂₁′ are as defined forR₁ to R₄, R₁₁ and R₁₂ in formula (1).

[0097] The compound of formula (11) and the compound of formula (12) arenot definitely distinguishable. Depending on the conjugated electronstate, it may take the form of either the compound of formula (11) orthe compound of formula (12). However, the invention favors the form ofthe compound of formula (12).

[0098] Shown below are the synthesis schemes of these synthesisprocesses.

[0099] Second Embodiment: Suzuki Coupling via Boronized Derivative

[0100] The second embodiment of the inventive synthesis process involvesusing a 1,8-dihalogenated naphthalene derivative of formula (1) and anaphthyl-1,8-diboronic acid derivative of the following formula (7), andsubjecting them to Suzuki coupling reaction for thereby synthesizing aperylene derivative of formula (2).

[0101] In formula (7), Z is a boronic acid derivative, and R₁ to R₄, R₁₁and R₁₂ are as defined for R₁ to R₄, R₁₁ and R₁₂ in formula (1). As theboronic acid derivative represented by Z, boronic acid B(OH)₂ is oftenused although derivatives having equivalent action are inclusive.

[0102] In Suzuki coupling reaction, the compounds of formulae (1) and(7) are treated in a solvent which inert to the reaction, in thepresence of a base and a palladium catalyst, and at a temperature ofroom temperature to 125° C. for 10 minutes to 24 hours, obtaining areaction product.

[0103] The solvent used herein is not critical, and examples thereofinclude aromatic hydrocarbons (e.g., benzene and toluene), ethers (e.g.,tetrahydrofuran and dioxane), amides (e.g., dimethylformamide anddimethylacetamide), esters (e.g., ethyl acetate), alcohols (e.g.,methanol), and ketones (e.g., acetone and cyclohexanone).

[0104] Alternatively, a perylene derivative of formula (4) can besynthesized by using a 3,4-dihalogenated fluoranthene derivative offormula (3) and a fluorantheno-1,8-diboronic acid derivative of thefollowing formula (8), and subjecting them to Suzuki coupling reaction.

[0105] In formula (8), Z is a boronic acid derivative, and R₁ to R₆, R₂₁and R₂₂ are as defined for R₁ to R₆, R₂₁ and R₂₂ in formula (3).

[0106] Moreover, a perylene derivative of formula (6) can be synthesizedby using a 3,4-dihalogenated benzofluoranthene derivative of formula (5)and a dibenzofluorantheno-1,8-diboronic acid derivative of the followingformula (9), and subjecting them to Suzuki coupling reaction.

[0107] In formula (9), Z is a boronic acid derivative.

[0108] Shown below are the synthesis schemes of these synthesisprocesses.

[0109] Third Embodiment: Coupling via Halogenation and Boron Derivative

[0110] The third embodiment of the invention is a combination ofhalogenation followed by coupling according to the first embodiment withcoupling via boron derivative according to the second embodiment. Thatis, the third embodiment is a perylene derivative synthesis processinvolving using a naphthalene derivative of the following formula (13)and subjecting it to Suzuki coupling reaction for thereby synthesizing adesired perylene derivative.

[0111] X is Cl, Br or I, and Z is a boronic acid derivative. R₁ to R₄,R₁₁ and R₁₂ in formula (13) are as defined in formula (1). X and Z arethe same as in the first and second embodiments, with their preferredexamples being also the same. The same applies to formulae (14) and (15)below.

[0112] Also, a perylene derivative can be synthesized by using afluoranthene derivative of the following formula (14), and subjecting itto Suzuki coupling reaction.

[0113] X is Cl, Br or I, and Z is a boronic acid derivative. R₁ to R₆,R₂₁ and R₂₂ in formula (14) are as defined in formula (3).

[0114] Further, a perylene derivative can be synthesized by using abenzofluoranthene derivative of the following formula (15), andsubjecting it to Suzuki coupling reaction.

[0115] X is Cl, Br or I, and Z is a boronic acid derivative. R₁ to R₈,R₃₁ and R₃₂ in formula (15) are as defined in formula (5).

[0116] Fourth Embodiment: Synthesis from Bishalogenated Naphthalene

[0117] The inventive process is characterized by coupling reaction usinga site modified by halogenation and optionally, a site modified with aboronic acid derivative. For these two bonding sites, it is acceptablewhether the two sites are simultaneously bonded, or the two sites aresequentially bonded one by one. Also for the modification sites, it isacceptable whether the two sites are simultaneously modified, or the twosites are sequentially modified one by one.

[0118] Accordingly, the inventive process encompasses a processcomprising the steps of using a bisnaphthalene derivative of thefollowing formula (16) as a starting reactant or intermediate, andsubjecting it to coupling reaction for thereby synthesizing a perylenederivative of the following formula (2).

[0119] R₁ to R₄, R₁₁ and R₁₂ in formula (16) are as defined for R₁ toR₄, R₁₁ and R₁₂ in formula (1). R₁′ to R₄′, R₁₁′ and R₁₂′ in formula (2)are as defined for R₁ to R₄, R₁₁ and R₁₂ in formula (1). R₁ to R₄, R₁₁and R₁₂ and R₁′ to R₄′, R₁₁′ and R₁₂′ may be the same or different. Xstands for a halogen atom, the detail of which is the same as describedin formula (1). In some cases, one X may be a boronic acid derivativerepresented by Z.

[0120] The inventive process is especially effective for synthesizingthe compounds of formula (6). It is preferred in formula (6) that R₁ toR₈, R₃₁, R₃₂, R₁′ to R₈′, R₃₁′ and R₃₂′ stand for substituted orunsubstituted aryl, alkyl, alkenyl, alkoxy or aryloxy radicals.

[0121] In the compounds of formula (6), it is further preferred that anyone or more of R₁ to R₈, R₃₁, R₃₂, R₁′ to R₈′, R₃₁′ and R₃₂′ stand forortho-substituted phenyl radicals. Using the inventive process, thosecompounds having a substituent radical at a specific position such asortho-substituted compounds can be readily produced. Similarly,compounds which are vertically or laterally asymmetric can be readilyproduced.

[0122] Especially, the compounds of formula (6) wherein either one orboth (vertical) of either one or both (lateral) of R₅ and R₆, and R₅′and R₆′ be ortho-substituted phenyl radicals.

[0123] The introduction of a substituent radical at the ortho-positionholds down the propensity for the compound to decompose upon sublimationpurification. Fluorescence is also improved by introducing a substituentradical at the ortho-position.

[0124] The use of the ortho-substituted compound is effective forincreasing the fluorescent luminance and holding down the concentrationquenching of the EL device, thereby spreading the margin of the ELdopant and improving the freedom of design.

[0125] Specifically, the introduction of an ortho-substituted phenylradical has several advantages. The ortho-substituted phenyl radicalintroduced makes it possible to control the association of the peryleneskeleton by virtue of its steric hindrance, to improve the solubility insolvents and to purify the compound to a high purity. For the samereason, sublimation purification becomes possible at a lower temperatureand entails little decomposition. This is also advantageous in obtaininga high purity material. Using such a pure material, an organic EL devicehaving a high emission efficiency is obtainable because the deactivationof excitons by impurities is minimized.

[0126] Another reason accounting for the high emission efficiency isthat the association between similar or distinct molecules in the lightemitting layer is suppressed whereby concentration quenching isrestrained.

[0127] Illustrative, preferred examples of the compounds having formulae(2), (4) and (6) are given below.

[0128] More preferred compounds are illustrated below.

[0129] The diindeno[1,2,3-cd:1′, 2′, 3′-lm]perylene derivative of theabove formula (6) should preferably have a vibration structure in bothan excitation spectrum and a fluorescence spectrum. The presence of sucha vibration structure is ascertainable by the appearance of two or morepeaks in each of the spectra.

[0130] More preferably, a host material doped with the indenoperylenederivative prior to use has such a vibration structure.

[0131] The possession of a vibration structure leads to the manufactureof an organic EL device having improved temperature characteristics.

[0132] It is believed that a drop of EL luminous efficiency bytemperature is due to thermal relaxation entailing a change ofconformation in the excited state. Once a change of conformation in theexcited state occurs, the overlap of molecular orbital function betweenthe ground state and the excited state changes so that the fluorescencespectrum does not become a mirror image of the absorption spectrum. Thefluorescence spectrum of a compound which can take a plurality ofconformations in the excited state is the total of various vibrationstructures and thus becomes a broad spectrum apparently free of avibration structure.

[0133] Accordingly, an organic compound which exhibits a vibrationstructure in the fluorescence spectrum and specifically, a compoundwhose vibration structure is a mirror image of the absorption spectrumexperiences a minimal change of conformation in the excited state andtherefore, when used as a luminescent material in an organic EL device,enables to produce a device having improved temperature characteristicsas demonstrated by a minimal drop of EL luminous efficiency bytemperature during driving.

[0134] For the same reason as above, the organic compound shouldpreferably have a Stokes shift of up to 0.1 eV, especially up to 0.05eV. The lower limit of Stokes shift is not critical although it isusually about 0.01 eV.

[0135] Another factor that governs the temperature characteristics of anorganic EL device is the thermal excitation of carriers from the traplevel. Especially in a doped light emitting layer, the dopant creates atrap level. Upon a temperature change, the hopping probability ofcarriers by thermal excitation changes. This sometimes results inchanges of the carrier balance in the light emitting layer, leading totemperature dependent characteristics with a high efficiency. Incontrast, the device of the invention has a minimized thermal change ofthe trapping of the light emitting layer, that is, minimized temperaturedependence of efficiency.

[0136] In a preferred embodiment, the host material, especially at leastone of the organic compounds of formula (I) shown later, in a lightemitting layer has a greater electron affinity than an electrontransporting layer and/or a hole transporting layer. If the hostmaterial in a light emitting layer has a greater electron affinity thanan electron transporting layer and/or a hole transporting layer, theinjection efficiency of electrons into the light emitting layerincreases and electrons are blocked at the hole transporting layerinterface, leading to an improvement in luminous efficiency and hence,device lifetime.

[0137] One class of organic compounds useful as the host materialaccording to the invention have a basic skeleton of the followingformula (I).

[0138] In the device of the invention, the use of the naphthacenederivative, preferably as the host material, helps induce strong lightemission from the dopant.

[0139] Naphthacene derivatives belong to a class of preferable organiccompounds, especially effective as the host material, among others. Forexample, the fluorescence intensity of a film of a naphthacenederivative (serving as the host material) doped with 1 wt % of adibenzo[f,f′]diindeno[1,2,3-cd:1′, 2′, 3′-lm]perylene derivative, asmeasured on photoexcitation, is about 3 times the fluorescenceintensities of films of other organic compounds (e.g., Alq3) as thehost.

[0140] The reason why such intense fluorescence is produced ispresumably that the combination of a naphthacene derivative with theabove dopant is an ideal combination that avoids interaction such asformation of an exciplex, and bipolar interaction between the respectivemolecules maintains a high intensity of fluorescence.

[0141] In the event of a red dopant, since the energy gap of anaphthacene derivative is relatively approximate to that of the dopant,an energy transfer phenomenon due to emission resorption takes place aswell as energy transfer by electron exchange. This accounts for a highfluorescence intensity as well.

[0142] The combination with the above host material minimizes theconcentration quenching of the dopant, which also contributes to a highfluorescence intensity.

[0143] In an exemplary organic EL device which was fabricated using theabove doped film as a light emitting layer, a luminance of at least 600cd/m² at maximum was obtained at a current density of 10 mA/cm², and thedrive voltage at this time was as low as about 6 V. When operated at acurrent density of about 600 mA/cm², the device consistently produced aluminance of greater than about 20,000 cd/m². As compared with otherorganic compounds (e.g., Alq3) serving as the host, this provides aluminous efficiency greater by a factor of about 4 when assessed interms of current efficiency, and because of possible driving at a lowervoltage, a luminous efficiency greater by a factor of about 5 whenassessed in terms of power efficiency. In the event of doping with a reddopant as in the above example, entailing the high efficiency of energytransfer from the host to the dopant, the device is characterized by ahigh chromatic purity in that only the dopant produces light emission,with little light emission from the host being observable.

[0144] It is believed that such a very high luminous efficiency exertedwhen organic EL devices are fabricated is due to the effects of animproved recombination probability of carriers in the light emittinglayer and a singlet excitation state that the dopant forms as a resultof energy transfer from the triplet excitation state of naphthacene, aswell as the above-mentioned mechanism of providing a high fluorescenceintensity.

[0145] As opposed to conventional organic EL devices whose drive voltageis increased by carrier trapping of the dopant, the inventive organic ELdevice using the above-mentioned light emitting layer has a very lowdrive voltage, because the order of carrier trapping of the dopant islow and high efficiency light emission is accomplished by theabove-mentioned mechanism. Another probable reason is the ease ofinjection of carriers into the light emitting layer.

[0146] Since the naphthacene derivative is very stable and highlydurable against carrier injection, the device fabricated using the abovehost-dopant combination has a very long lifetime. For example, anorganic EL device having a light emitting layer of a specificnaphthacene derivative doped with 1 wt % of adibenzo[f,f′]diindeno-[1,2,3-cd:1′, 2′, 3′-lm]perylene derivative ishighly durable as demonstrated by its ability to sustain a luminance ofat least 2,400 cd/m² over a period of 1,000 hours or longer, with anattenuation of less than about 1%, when driven at 50 mA/cm².

[0147] In organic EL devices as mentioned above, the dopantconcentration ensuring a chromatic purity and maximum efficiency isabout 1% by weight although dopant concentrations of about 2 or 3% byweight lead to devices which are practically acceptable albeit a drop ofless than about 10%.

[0148] In formula (I), Q¹ to Q⁴ are independently selected from amonghydrogen and substituted or unsubstituted alkyl, aryl, amino,heterocyclic and alkenyl radicals. Preferred are aryl, amino,heterocyclic and alkenyl radicals. It is also desirable that Q² and Q³are these substituent radicals and Q¹ and Q⁴ are hydrogen.

[0149] The aryl radicals represented by Q¹ to Q⁴ may be monocyclic orpolycyclic, inclusive of fused rings and a collection of rings. Thosearyl radicals having 6 to 30 carbon atoms in total are preferred andthey may have substituents.

[0150] Preferred examples of the aryl radical represented by Q¹ to Q⁴include phenyl, o-, m- and p-tolyl, pyrenyl, perylenyl, coronenyl, 1-and 2-naphthyl, anthryl, o-, m- and p-biphenylyl, terphenyl andphenanthryl.

[0151] The amino radicals represented by Q¹ to Q⁴ may be selected fromamong alkylamino, arylamino, aralkylamino and analogous radicals. Theypreferably have aliphatic radicals having 1 to 6 carbon atoms in totaland/or aromatic carbocyclic radicals having 1 to 4 rings. Illustrativeexamples include dimethylamino, diethylamino, dibutylamino,diphenylamino, ditolylamino, bisdiphenylylamino, and bisnaphthylaminoradicals.

[0152] The heterocyclic radicals represented by Q¹ to Q⁴ include 5- or6-membered ring aromatic heterocyclic radicals containing O, N or S as ahetero atom, and fused polycyclic aromatic heterocyclic radicals having2 to 20 carbon atoms.

[0153] The alkenyl radicals represented by Q¹ to Q⁴ are preferably thosehaving a phenyl radical as at least one substituent, such as 1- and2-phenylalkenyl, 1,2- and 2,2-diphenylalkenyl, and1,2,2-triphenylalkenyl although unsubstituted alkenyl radicals areacceptable.

[0154] Examples of the aromatic heterocyclic radicals and fusedpolycyclic aromatic heterocyclic radicals include thienyl, furyl,pyrolyl, pyridyl, quinolyl, and quinoxalyl radicals.

[0155] When Q¹ to Q⁴ are substituted radicals, at least two of thesubstituents are preferably aryl, amino, heterocyclic, alkenyl oraryloxy radicals. These aryl, amino, heterocyclic and alkenyl radicalsare as illustrated above for Q¹ to Q⁴.

[0156] The aryloxy radicals to substitute on Q¹ to Q⁴ are preferablythose of aryl radicals having 6 to 18 carbon atoms in total, forexample, o-, m- and p-phenoxy.

[0157] At least two of these substituents may form a fused ring. Also,these substituents may be further substituted ones, in which preferredsubstituents are as described above.

[0158] When Q¹ to Q⁴ have substituents, it is preferred that at leasttwo of the substituents have the above-described substituents. Theposition of substitution is not particularly limited and may be a meta,para or ortho position. Q¹ and Q⁴, and Q² and Q³ in the respective pairsare preferably identical although they may be different.

[0159] Q⁵, Q⁶, Q⁷ and Q⁸ are independently selected from among hydrogenand alkyl, aryl, amino, heterocyclic and alkenyl radicals which may havesubstituents.

[0160] The alkyl radicals represented by Q⁵, Q⁶, Q⁷ and Q⁸ arepreferably those of 1 to 6 carbon atoms, which may be straight orbranched. Preferred examples of the alkyl radical include methyl, ethyl,n- and i-propyl, n-, i-, sec- and tert-butyl, n-, i-, neo- andtert-pentyl.

[0161] The aryl, amino and alkenyl radicals represented by Q⁵, Q⁶, Q⁷and Q⁸ are as illustrated above for Q¹ to Q⁴. Q⁵ and Q⁶, and Q⁷ and Q⁸in the respective pairs are preferably identical although they may bedifferent.

[0162] It is preferred that rubrene wherein all Q¹ to Q⁴ are phenyl andQ⁵, Q⁶, Q⁷ and Q⁸ are hydrogen be excluded.

[0163] The light emitting layer containing the host material and thedopant as mentioned above has functions of injecting holes andelectrons, transporting them, and recombining holes and electrons tocreate excitons. The use of relatively electronically neutral compoundsin the light emitting layer in addition to the compounds of theinvention enables easy and well-balanced injection and transportation ofelectrons and holes.

[0164] The host material may be used alone or in admixture of two ormore. When a mixture of two or more host materials is used, the mixratio is arbitrary. The host material is preferably contained in anamount of 80 to 99.9%, more preferably 90 to 99.9%, even more preferably95.0 to 99.5% by weight of the light emitting layer.

[0165] The thickness of the light emitting layer preferably ranges fromthe thickness corresponding to a single molecule layer to less than thethickness of an organic compound layer, for example, preferably from 1to 85 nm, more preferably 5 to 60 nm, and most preferably 5 to 50 nm.

[0166] Preferably the mix layer is formed by a co-deposition process ofevaporating the compounds from distinct sources. If both the compoundshave equal or very close vapor pressure or evaporation temperature, theymay be pre-mixed in a common evaporation boat, from which they areevaporated together. The mix layer is preferably a uniform mixture ofboth the compounds although the compounds can be present in island form.The light emitting layer is generally formed to a predeterminedthickness by evaporating an organic fluorescent material or coating adispersion thereof in a resin binder.

[0167] One exemplary construction of the organic EL light emittingdevice fabricated using the inventive compounds has on a substrate, ahole injecting electrode, a hole injecting and transporting layer, alight emitting and electron injecting and transporting layer, and anelectron injecting electrode in the described order. If desired, aprotective electrode, an auxiliary electrode and a sealing layer may beprovided on the electron injecting electrode.

[0168] The organic EL device of the invention is not limited to theabove exemplary construction and may have various other constructions.In another exemplary construction, the light emitting layer is providedsingly and an electron injecting and transporting layer is interposedbetween the light emitting layer and the electron injecting electrode.Also, the light emitting layer may be mixed with the hole injecting andtransporting layer, if desired.

[0169] The thicknesses of the light emitting layer, hole injecting andtransporting layer, and electron injecting and transporting layer arenot critical and vary with a particular formation technique. Usuallyeach layer is about 5 to 500 nm thick, especially about 10 to 300 nmthick.

[0170] The thicknesses of the hole injecting and transporting layer andelectron injecting and transporting layer are equal to or range fromabout {fraction (1/10)} to 10 times the thickness of the light emittinglayer although they depend on the design of a recombination/lightemitting region. When the electron or hole injecting and transportinglayer is divided into an injecting layer and a transporting layer,preferably the injecting layer is at least 1 nm thick and thetransporting layer is at least 1 nm thick. The upper limit of thicknessis generally about 500 nm for the injecting layer and about 500 nm forthe transporting layer. The same applies when two injecting andtransporting layers are provided.

[0171] The hole injecting and transporting layer has functions offacilitating injection of holes from the hole injecting electrode,transporting them stably, and blocking electrons. The electron injectingand transporting layer has functions of facilitating injection ofelectrons from the electron injecting electrode, transporting themstably, and blocking holes. These layers are effective for increasingthe number of holes and electrons injected into the light emitting layerand confining holes and electrons therein for optimizing therecombination region to improve light emission efficiency.

[0172] In the hole injecting and transporting layer, there may be usedvarious organic compounds as described, for example, in JP-A 63-295695,JP-A 2-191694, JP-A 3-792, JP-A 5-234681, JP-A 5-239455, JP-A 5-299174,JP-A 7-126225, JP-A 7-126226, JP-A 8-100172, and EPO 650955A1. Exemplaryare tetraarylbenzidine compounds (triaryldiamines or triphenyl-diamines:TPD), aromatic tertiary amines, hydrazone derivatives, carbazolederivatives, triazole derivatives, imidazole derivatives, oxadiazolederivatives having an amino radical, and polythiophenes. Two or more ofthese compounds may be used, and on such combined use, they may beformed as a laminate of separate layers or mixed.

[0173] Where the hole injecting and transporting layer is formedseparately as a hole injecting layer and a hole transporting layer, twoor more compounds are selected in a proper combination from thecompounds commonly used in hole injecting and transporting layers. Inthis regard, it is preferred to laminate layers in such an order that alayer of a compound having a lower ionization potential may be disposedadjacent the hole injecting electrode (ITO). It is also preferred to usea compound having good thin film forming ability at the hole injectingelectrode surface. The order of lamination also applies where aplurality of hole injecting and transporting layers are provided. Suchan order of lamination is effective for lowering the drive voltage andpreventing current leakage and the development and growth of dark spots.Since evaporation is utilized in the manufacture of devices, films asthin as about 1 to 10 nm can be formed uniform and pinhole-free, whichrestrains any change in color tone of light emission and a drop ofefficiency by re-absorption even if a compound having a low ionizationpotential and absorption in the visible range is used in the holeinjecting layer. Like the light emitting layer, the hole injecting andtransporting layer may be formed by evaporating the above-mentionedcompounds.

[0174] In the electron injecting and transporting layer, there may beused quinoline derivatives including organic metal complexes having8-quinolinol or a derivative thereof as a ligand such astris(8-quinolinolato)aluminum (Alq3), oxadiazole derivatives, perylenederivatives, pyridine derivatives, pyrimidine derivatives, quinoxalinederivatives, diphenylquinone derivatives, nitro-substituted fluorenederivatives, etc. The electron injecting and transporting layer can alsoserve as the light emitting layer, and in such a case, the lightemitting layer according to the invention is preferably employed. Likethe light emitting layer, the electron injecting and transporting layermay be formed by evaporation or the like.

[0175] Where the electron injecting and transporting layer is formedseparately as an electron injecting layer and an electron transportinglayer, two or more compounds are selected in a proper combination fromthe compounds commonly used in electron injecting and transportinglayers. In this regard, it is preferred to stack layers in such an orderthat a layer of a compound having a greater electron affinity may bedisposed adjacent the electron injecting electrode. The order ofstacking also applies where a plurality of electron injecting andtransporting layers are provided.

[0176] In forming the hole injecting and transporting layer, the lightemitting layer, and the electron injecting and transporting layer,vacuum evaporation is preferably used because homogeneous thin films areavailable. By utilizing vacuum evaporation, there is obtained ahomogeneous thin film which is amorphous or has a crystal grain size ofup to 0.1 μm. If the grain size is more than 0.1 μm, uneven lightemission would take place and the drive voltage of the device must beincreased with a substantial drop of hole injection efficiency.

[0177] The conditions for vacuum evaporation are not critical although avacuum of 10⁻⁴ Pa or lower and a deposition rate of about 0.01 to 1nm/sec are preferred. It is also preferred to successively form layersin vacuum because the successive formation in vacuum can avoidadsorption of impurities on the interface between the layers, thusensuring better performance. Also, the drive voltage of a device can bereduced and the development and growth of dark spots be restrained.

[0178] In the embodiment wherein the respective layers are formed byvacuum evaporation, where it is desired for a single layer to containtwo or more compounds, preferably boats having the compounds receivedtherein are individually temperature controlled to achieveco-deposition.

[0179] The electron injecting electrode is preferably made of metals,alloys or intermetallic compounds having a work function of up to 4 eV.With a work function of more than 4 eV, the electron injectingefficiency lowers and consequently, the light emission efficiencylowers. Examples of the metal having a work function of up to 4 eV ofwhich the electron injecting electrode film is constructed includealkali metals such as Li, Na and K, alkaline earth metals such as Mg,Ca, Sr and Ba, rare earth metals such as La and Ce, and Al, In, Ag, Sn,Zn, and Zr. Examples of the film-forming alloy having a work function ofup to 4 eV include Ag—Mg (Ag: 0.1 to 50 at %), Al—Li (Li: 0.01 to 12 at%), In—Mg (Mg: 50 to 80 at %), and Al—Ca (Ca: 0.01 to 20 at %). Thesematerials may be present alone or in combination of two or more. Wheretwo or more materials are combined, their mixing ratio is arbitrary. Itis also acceptable that an oxide or halide of an alkali metal, alkalineearth metal or rare earth metal is thinly deposited and a supportingelectrode (auxiliary electrode or wiring electrode) of aluminum etc. isused.

[0180] The electron injecting electrode may be formed by evaporation orsputtering.

[0181] The electron injecting electrode may have at least a sufficientthickness to effect electron injection, for example, a thickness of atleast 0.1 nm. Although the upper limit is not critical, the electrodethickness is typically about 0.1 to about 500 nm.

[0182] The hole injecting electrode is preferably formed of such amaterial to such a thickness that the electrode may have a transmittanceof at least 80% of emitted light. Illustratively, oxide transparentconductive thin films are preferred. For example, materials based ontin-doped indium oxide (ITO), zinc-doped indium oxide (IZO), indiumoxide (In₂O₃), tin oxide (SnO₂) or zinc oxide (ZnO) are preferable.These oxides may deviate somewhat from their stoichiometry. Anappropriate proportion of SnO₂ mixed with In₂O₃ is 1 to 20%, morepreferably 5 to 12% by weight. An appropriate proportion of ZnO mixedwith In₂O₃ is 12 to 32% by weight.

[0183] The hole injecting electrode should preferably have a lighttransmittance of at least 80%, especially at least 90% in the lightemission band, typically from 350 to 800 nm, and especially at eachlight emission. Since the emitted light is generally taken out throughthe hole injecting electrode, with a lower transmittance, the lightemitted by the light emitting layer would be attenuated through theelectrode, failing to provide a luminance necessary as a light emittingdevice. It is noted that only the side from which the emitted lightexits has a transmittance of at least 80%.

[0184] The hole injecting electrode has at least a sufficient thicknessto effect hole injection, preferably a thickness of 50 to 500 nm,especially 50 to 300 nm. Although the upper limit of the electrodethickness is not critical, a too thick electrode would have the risk ofseparation. Too thin an electrode would have problems with respect tofilm strength during fabrication, hole transporting ability, andresistance value.

[0185] In depositing the hole injecting electrode, a sputtering processis preferred. The sputtering process may be a high-frequency sputteringprocess using an RF power supply although a dc sputtering process ispreferably used when the ease of control of physical properties of thehole injecting electrode being deposited and the flatness of thedeposited film are taken into account.

[0186] A protective film may be formed if necessary. The protective filmmay be formed using an inorganic material such as SiOx or an organicmaterial such as Teflon™. The protective film may be either transparentor opaque and have a thickness of about 50 to 1,200 nm. Apart from thereactive sputtering process mentioned above, the protective film mayalso be formed by an ordinary sputtering or evaporation process.

[0187] Further, a sealing layer is preferably provided on the device inorder to prevent the organic layers and electrodes from oxidation. Inorder to prevent the ingress of moisture, the sealing layer is formed byattaching a sealing plate such as a glass plate to the substrate with anadhesive resin layer such as a commercially available low moistureabsorption photo-curable adhesive, epoxy base adhesive, silicone baseadhesive, or crosslinking ethylene-vinyl acetate copolymer adhesivesheet. Metal plates and plastic plates may also be used instead of theglass plate.

[0188] Transparent or translucent materials such as glass, quartz andresins are used as the substrate when the emitted light exits from thesubstrate side. The substrate may be provided with a color filter film,a fluorescent material-containing color conversion film or a dielectricreflecting film for controlling the color of light emission. In the caseof the inversely stacked layer structure, the substrate may be eithertransparent or opaque. For the opaque substrate, ceramic and othermaterials may be used.

[0189] The color filter film used herein may be a color filter as usedin liquid crystal displays and the like. The properties of a colorfilter may be adjusted in accordance with the light emission of theorganic EL device so as to optimize the extraction efficiency andchromatic purity.

[0190] It is also preferred to use a color filter capable of cuttingexternal light of short wavelength which is otherwise absorbed by the ELdevice materials and fluorescence conversion layer, because the lightresistance and display contrast of the device are improved.

[0191] Also, an optical thin film such as a dielectric multilayer filmmay be used instead of the color filter.

[0192] The organic EL device of the invention is constructed, as shownin FIG. 1, for example, to have on a substrate 1, a hole injectingelectrode (or anode) 2, a hole injecting layer 3, a hole transportinglayer 4, a light emitting layer 5, an electron injecting andtransporting layer 6, an electron injecting electrode (or cathode) 7 andoptionally, a protective electrode 8 in the described order. The orderof lamination may be inverse to the above-described order. The holeinjecting layer 3, hole transporting layer 4 and electron injecting andtransporting layer 6 may be omitted or either one of them may be acommon layer to the light emitting layer 5. Each of these constituentlayers may be adjusted optimum depending on the required function of thedevice.

[0193] The organic EL device of the invention is generally of the dc orpulse drive type while it can be of the ac drive type. The appliedvoltage is generally about 2 to 30 volts.

EXAMPLE

[0194] Synthesis Examples and Examples of the present invention aregiven below together with Comparative Examples for further illustratingthe invention.

Example 1 Synthesis of 1-o-biphenylyl-3-phenylisobenzofuran

[0195] In Ar, 3.9 g (1.68E-2 mol) of o-bromobiphenyl was dissolved in 30cm³ of tetrahydrofuran (THF) at −50° C. To the solution was added 10 cm³of a nBuLi hexane solution (1.5 mol/l). After 2 hours, 3 g (1.4E-2 mol)of 3-phenylphthalide was added to the solution while it was kept cooledat −50° C. After 2 hours, the reaction solution was allowed to resumeroom temperature, and 10 cm³ of a 35% aqueous hydrochloric acid wasadded thereto. After 1 hour, toluene extraction was carried out using aseparatory funnel, followed by thorough washing with distilled water.After the toluene solution was concentrated, the end product wasisolated by silica gel chromatography (developer, toluene:hexane=1:4).There was obtained 4 g (80%) of a yellow viscous substance emittingbluish green fluorescence.

Synthesis of 3,4-dibromo-(7-o-biphenylyl-12-phenyl)-benzo[k]fluoranthene

[0196] In toluene, 2.2 g (6.45E-3 mol) of1-o-biphenylyl-3-phenylisobenzofuran synthesized above and 2.0 g(6.45E-3 mol) of 5,6-dibromoacenaphthene were heated under reflux for 24hours. At the end of reaction, the precipitate was recovered, obtainingan intermediate. 1.6 g (41%) The intermediate, 1.6 g, was dissolved in150 cm³ of acetic acid by heating. To the solution, 20 cm³ of a 50%aqueous solution of HBr was added, and reaction effected at 120° C. for30 minutes. After cooling, the precipitate was recovered. The endproduct was isolated by silica gel chromatography (developer,toluene:hexane=1:3). There was obtained 1.0 g (70%) of a yellow powder.

Synthesis of dibenzo-((bis-o-biphenylyl)(-diphenyl))-perifuranthene

[0197] In 30 cm³ of DMF was dissolved 1.0 g (1.57E-3 mol) of3,4-dibromo-(7-o-biphenylyl-12-phenyl)benzo[k]fluoranthene synthesizedabove. To the solution, 0.52 g (1.9E-3 mol) of Ni(COD)₂, 1 ml ofcyclooctadiene (COD) and 0.12 g (1.57E-3 mol) of bipyridine were added,and reaction effected at 60° C. for 12 hours.

[0198] At the end of reaction, 30 cm³ of 1N aqueous hydrochloric acidand 30 cm³ of methanol were added whereby the end compound wasprecipitated and recovered. The end compound was isolated by silica gelchromatography (developer, toluene:hexane=1:3). There was obtained 0.67g (90%) of a bluish purple solid.

[0199] The compound in a dichloromethane solution exhibited fluorescencepeaks (EM) at a wavelength of 602 and 652 nm. The compound in adichloromethane solution exhibited fluorescence absorption peaks (EX) ata wavelength of 508, 547 and 593 nm.

[0200] Mass analysis: (M+1)⁺=957

[0201] Sublimation purification temperature: 430° C.

Example 2

[0202] Synthesis of 3,4-dibromofluoranthene Derivative

[0203] A series of 5,6-dibromofluoranthene derivatives are obtainable byeffecting Diels-Alder reaction between 5,6-dibromoacenaphthylene and abutadiene derivative and then effecting dehydrogenation reaction withdichiorodicyano-quinone (DDQ).

[0204] In xylene, 5 g (1.6E-2 mol) of 5,6-dibromoace-naphthylene and 3.3g (1.6E-2 mol) of 2,3-diphenylbutadiene were heated under reflux for 48hours, obtaining 5.6 g (70%) of an intermediate.

[0205] In toluene were dissolved 5 g (9.6E-3 mol) of the intermediateand 2.2 g (9.6E-3 mol) of dichiorodicyano-quinone (DDQ). By effectingreaction at 120° C. for 24 hours, 3.0 g (60%) of3,4-dibromo-8,9-diphenylfluoranthene was obtained.

Synthesis Route of dibenzotetraphenylperifuranthene via Suzuki Coupling

[0206] Reaction (1)

[0207] In Ar, 5.6 g (1.0E-2 mol) of3,4-dibromo(7,12-diphenyl)benzo[k]fluoranthene was dissolved in 100 cm³of dry THF, which was cooled at −40 to −50° C. To the solution, 14 cm³(1.0E-2×2.2 mol) of a nBuLi hexane solution (1.57 mol/l) was slowlyadded. The temperature was kept at −40 to −50° C. for 1 hour, afterwhich 3.2 g (1.0E-2×2.2 mol) of triethyl borate was slowly added. After2 hours, 50 cm³ of distilled water was added. Thereafter, ˜10% aqueoushydrochloric acid was added to the reaction solution until it turnedweakly acidic. The reaction solution was allowed to resume roomtemperature, neutralized with aqueous NaHCO₃, and combined withdistilled water. By vacuum distilling off the organic layer, theprecipitate was recovered.

[0208] The recovered material was washed with a large volume of water byagitation, followed by filtration. The recovered material was dissolvedin acetone, dried over MgSO₄, and precipitated again by adding hexane.

[0209] Yield 4 g (81%)

[0210] Reaction (2)

[0211] In nitrogen, 4 g (8.1E-3 mol) of(7,12-diphenyl)-benzo[k]fluoranthene-3,4-diboronic acid and 4.55 g(8.1E-3 mol) of 3,4-dibromobenzo[k]fluoranthene were dissolved in 150cm³ of a 1:1 solvent mixture of toluene and ethanol. Then 0.93 g(8.1E-3×2×0.05 mol) of tetrakis(triphenyl-phosphine)palladium(0)(Pd(PPh₃)₄) was added to the solution, which was heated at 85° C. in anoil bath. Then an aqueous solution of sodium carbonate which waspreviously prepared by dissolving 15 g of Na₂CO₃ in 50 cm³ of distilledwater was admitted into the solution, which was allowed to reactovernight. The reaction was followed by extraction with chloroform andthorough washing with distilled water.

[0212] The product was column purified using silica gel.

[0213] Yield 5.2 g (80%)

Example 3 Synthesis of dibenzotetraphenylperifuranthene

[0214] In 50 cm³ of DMF was dissolved 1.5 g (1.56E-3 mol) of3,3′-dibromo-4,4′-bis((7,12-diphenyl)benzo[k]fluoranthene) of theformula shown below. To the solution, 0.52 g (1.9E-3 mol) of Ni(COD)₂, 1ml of cyclooctadiene (COD) and 0.12 g (1.57E-3 mol) of bipyridine wereadded, and reaction effected at 80° C. for 12 hours.

Synthesis Example

[0215]

[0216] At the end of reaction, 30 cm³ of 1N aqueous hydrochloric acidand 30 cm³ of methanol were added whereby the end compound wasprecipitated and recovered. The end compound was isolated by silica gelchromatography (developer, toluene:hexane=1:3). There was obtained 1.1 g(90%) of a black solid.

[0217] The compound in a dichloromethane solution exhibited fluorescencepeaks (EM) at a wavelength of 600 and 650 nm.

[0218] The compound in a dichloromethane solution exhibited fluorescenceabsorption peaks (EX) at a wavelength of 508, 546 and 591 nm.

[0219] Mass analysis: (M+1)⁺=805

[0220] Sublimation purification temperature: 410° C.

Comparative Example Synthesis of dibenzotetraphenylperifuranthene

[0221] A mixture of 2 g (5E-3 mol) of(7,12-diphenyl)-benzo[k]fluoranthene and 3 g (2.6E-2 mol) of cobaltfluoride (CoF₃) was suspended in 100 ml of trifluoroacetic acid, whichwas heated under reflux for 40 hours. At the end of reaction, thereaction solution was poured into cold water and extracted withdichloromethane. By drying over magnesium sulfate and removing theorganic solvent, a black solid was obtained. It was purified by silicagel chromatography. There was obtained 1 g (50%) of a blackish purplesolid.

Synthesis of dibenzotetra(β-naphthyl)perifuranthene

[0222] A mixture of 2.52 g (5E-3 mol) of(7,12-bis(β-naphthyl))benzo[k]fluoranthene and 3 g (2.6E-2 mol) ofcobalt fluoride (CoF₃) was suspended in 100 ml of trifluoroacetic acid,which was heated under reflux for 40 hours. At the end of reaction, thereaction solution was poured into cold water and extracted withdichloromethane. By drying over magnesium sulfate and removing theorganic solvent, a black solid was obtained. It was purified by silicagel chromatography. There was obtained 0.2 g (8%) of a blackish purplesolid.

Synthesis of dibenzooctaphenylperifuranthene

[0223] A mixture of 2.79 g (5E-3 mol) of(7,9,10,12-tetraphenyl)benzo[k]fluoranthene and 3 g (2.6E-2 mol) ofcobalt fluoride (CoF₃) was suspended in 100 ml of trifluoroacetic acid,which was heated under reflux for 40 hours. At the end of reaction, thereaction solution was poured into cold water and extracted withdichloromethane. By drying over magnesium sulfate and removing theorganic solvent, a black solid was obtained. It was purified by silicagel chromatography. There was obtained 0.42 g (15%) of a blackish purplesolid.

Example 4

[0224] On a glass substrate, a transparent ITO electrode thin film wasdeposited to a thickness of 100 nm by RF sputtering and patterned. Theglass substrate having the transparent ITO electrode was subjected toultrasonic washing with neutral detergent, acetone, and ethanol, pulledup from boiling ethanol, and dried. The transparent electrode surfacewas further cleaned with UV/O₃. Thereafter, the substrate was secured bya holder in a vacuum evaporation chamber, which was evacuated to avacuum of 1×10⁻⁵ Pa or lower.

[0225] With the vacuum kept,N,N′-diphenyl-N,N′-bis[N-(4-methylphenyl)-N-phenyl-(4-aminophenyl)]-1,1′-biphenyl-4,4′-diamine(ATP) of the structure shown below was evaporated at a deposition rateof 0.1 nm/sec. to a thickness of 50 nm, forming a hole injecting layer.

[0226] Then, N,N,N′, N′-tetrakis(m-biphenyl)-1,1′-biphenyl-4,4′-diamine(TPD) of the structure shown below was evaporated at a deposition rateof 0.1 nm/sec to a thickness of 20 nm, forming a hole transportinglayer.

[0227] With the vacuum kept, a host material of the structure shownbelow and a mixture of dopants of the structure shown below wereevaporated in a weight ratio of 99:1 and at an overall deposition rateof 0.1 nm/sec to a thickness of 40 nm, forming a light emitting layer.

[0228] Next, with the vacuum kept, tris(8-quinolinolato)-aluminum of thestructure shown below was evaporated at a deposition rate of 0.1 nm/secto a thickness of 30 nm, forming an electron transporting layer.

[0229] Next, with the vacuum kept, LiF was evaporated at a depositionrate of 0.01 nm/sec to a thickness of 0.3 nm, forming an electroninjecting electrode. Finally, aluminum was evaporated to a thickness of150 nm to form a protective electrode, completing an organic EL device.

[0230] A dc voltage was applied across the organic EL device. Initially,the device was found to produce light emission to a luminance of 630cd/m² when operated at a current density of 10 mA/cm² and a drivevoltage of 6.5 volts. The chromaticity coordinates (x, y) were (0.65,0.35).

Benefits of the Invention

[0231] It is evident from the foregoing description that the inventionprovides a perylene derivative synthesis process featuring asatisfactory yield and improved preparation efficiency, perylenederivatives obtained by the process, and organic EL devices using thesame.

What is claimed is:
 1. A process for synthesizing a perylene derivativecomprising the steps of halogenating a reactant and subjecting thehalogenated reactant at its halogenated site to coupling reaction or thesteps of using a halogenated reactant and a boronized reactant andsubjecting them at their halogenated and boronized sites to Suzukicoupling reaction, or combining the foregoing steps.
 2. A process forsynthesizing a perylene derivative according to claim 1 wherein a1,8-dihalogenated naphthalene derivative of the following formula (1):

wherein X is Cl, Br or I, R₁ to R₄, R₁₁ and R₁₂ each are a hydrogenatom, a straight, branched or cyclic alkyl radical which may besubstituted, a straight, branched or cyclic alkoxy radical which may besubstituted, a straight, branched or cyclic alkylthio radical which maybe substituted, a straight, branched or cyclic alkenyl radical which maybe substituted, a straight, branched or cyclic alkenyloxy radical whichmay be substituted, a straight, branched or cyclic alkenylthio radicalwhich may be substituted, a substituted or unsubstituted aralkylradical, a substituted or unsubstituted aralkyloxy radical, asubstituted or unsubstituted aralkylthio radical, a substituted orunsubstituted aryl radical, a substituted or unsubstituted aryloxyradical, a substituted or unsubstituted arylthio radical, a substitutedor unsubstituted amino radical, a cyano radical, a hydroxyl radical, a—COOM₁ radical (wherein M₁ is a hydrogen atom, a straight, branched orcyclic alkyl radical which may be substituted, a straight, branched orcyclic alkenyl radical which may be substituted, a substituted orunsubstituted aralkyl radical, or a substituted or unsubstituted arylradical), a —COM₂ radical (wherein M₂ is a hydrogen atom, a straight,branched or cyclic alkyl radical which may be substituted, a straight,branched or cyclic alkenyl radical which may be substituted, asubstituted or unsubstituted aralkyl radical, a substituted orunsubstituted aryl radical, or an amino radical), or a —OCOM₃ radical(wherein M₃ is a straight, branched or cyclic alkyl radical which may besubstituted, a straight, branched or cyclic alkenyl radical which may besubstituted, a substituted or unsubstituted aralkyl radical, or asubstituted or unsubstituted aryl radical), and at least two adjoiningradicals selected from among R₁ to R₄, R₁₁ and R₁₂ may bond or fusetogether to form a substituted or unsubstituted carbocyclic aliphaticring, aromatic ring or fused aromatic ring with the carbon atoms onwhich they substitute, with the proviso that when the carbocyclicaliphatic ring, aromatic ring or fused aromatic ring has substituentradicals, the substituent radicals are the same as R₁ to R₄, R₁₁ andR₁₂, is subjected to coupling reaction to synthesize a perylenederivative of the following formula (2):

wherein R₁′ to R₄′, R₁₁′ and R₁₂′ are as defined for R₁ to R₄, R₁₁ andR₁₂ in formula (1), and R₁ to R₄, R₁₁ and R₁₂ and R₁′ to R₄′, R₁₁′ andR₁₂′ may be the same or different.
 3. A process for synthesizing aperylene derivative according to claim 1 wherein a 3,4-dihalogenatedfluoranthene derivative of the following formula (3):

wherein X is Cl, Br or I, R₁ to R₆, R₂₁ and R₂₂ each are a hydrogenatom, a straight, branched or cyclic alkyl radical which may besubstituted, a straight, branched or cyclic alkoxy radical which may besubstituted, a straight, branched or cyclic alkylthio radical which maybe substituted, a straight, branched or cyclic alkenyl radical which maybe substituted, a straight, branched or cyclic alkenyloxy radical whichmay be substituted, a straight, branched or cyclic alkenylthio radicalwhich may be substituted, a substituted or unsubstituted aralkylradical, a substituted or unsubstituted aralkyloxy radical, asubstituted or unsubstituted aralkylthio radical, a substituted orunsubstituted aryl radical, a substituted or unsubstituted aryloxyradical, a substituted or unsubstituted arylthio radical, a substitutedor unsubstituted amino radical, a cyano radical, a hydroxyl radical, a—COOM₁ radical (wherein M₁ is a hydrogen atom, a straight, branched orcyclic alkyl radical which may be substituted, a straight, branched orcyclic alkenyl radical which may be substituted, a substituted orunsubstituted aralkyl radical, or a substituted or unsubstituted arylradical), a —COM₂ radical (wherein M₂ is a hydrogen atom, a straight,branched or cyclic alkyl radical which may be substituted, a straight,branched or cyclic alkenyl radical which may be substituted, asubstituted or unsubstituted aralkyl radical, a substituted orunsubstituted aryl radical, or an amino radical), or a —OCOM₃ radical(wherein M₃ is a straight, branched or cyclic alkyl radical which may besubstituted, a straight, branched or cyclic alkenyl radical which may besubstituted, a substituted or unsubstituted aralkyl radical, or asubstituted or unsubstituted aryl radical), and at least two adjoiningradicals selected from among R₁ to R₆, R₂₁ and R₂₂ may bond or fusetogether to form a substituted or unsubstituted carbocyclic aliphaticring, aromatic ring or fused aromatic ring with the carbon atoms onwhich they substitute, is subjected to coupling reaction to synthesize aperylene derivative of the following formula (4):

wherein R₁′ to R₆′, R₂₁′ and R₂₂′ are as defined for R₁ to R₆, R₂₁ andR₂₂ in formula (3), and R₁ to R₆, R₂₁ and R₂₂ and R₁′ to R₆′, R₂₁′ andR₂₂′ may be the same or different.
 4. A process for synthesizing aperylene derivative according to claim 1 wherein a 3,4-dihalogenatedbenzofluoranthene derivative of the following formula (5):

wherein X is Cl, Br or I, R₁ to R₈, R₃₁ and R₃₂ each are a hydrogenatom, a straight, branched or cyclic alkyl radical which may besubstituted, a straight, branched or cyclic alkoxy radical which may besubstituted, a straight, branched or cyclic alkylthio radical which maybe substituted, a straight, branched or cyclic alkenyl radical which maybe substituted, a straight, branched or cyclic alkenyloxy radical whichmay be substituted, a straight, branched or cyclic alkenylthio radicalwhich may be substituted, a substituted or unsubstituted aralkylradical, a substituted or unsubstituted aralkyloxy radical, asubstituted or unsubstituted aralkylthio radical, a substituted orunsubstituted aryl radical, a substituted or unsubstituted aryloxyradical, a substituted or unsubstituted arylthio radical, a substitutedor unsubstituted amino radical, a cyano radical, a hydroxyl radical, a—COOM₁ radical (wherein M₁ is a hydrogen atom, a straight, branched orcyclic alkyl radical which may be substituted, a straight, branched orcyclic alkenyl radical which may be substituted, a substituted orunsubstituted aralkyl radical, or a substituted or unsubstituted arylradical), a —COM₂ radical (wherein M₂ is a hydrogen atom, a straight,branched or cyclic alkyl radical which may be substituted, a straight,branched or cyclic alkenyl radical which may be substituted, asubstituted or unsubstituted aralkyl radical, a substituted orunsubstituted aryl radical, or an amino radical), or a —OCOM₃ radical(wherein M₃ is a straight, branched or cyclic alkyl radical which may besubstituted, a straight, branched or cyclic alkenyl radical which may besubstituted, a substituted or unsubstituted aralkyl radical, or asubstituted or unsubstituted aryl radical), and at least two adjoiningradicals selected from among R₁ to R₈, R₃₁ and R₃₂ may bond or fusetogether to form a substituted or unsubstituted carbocyclic aliphaticring, aromatic ring or fused aromatic ring with the carbon atoms onwhich they substitute, is subjected to coupling reaction to synthesize aperylene derivative of the following formula (6):

wherein R₁′ to R₈′, R₃₁′ and R₃₂′ are as defined for R₁ to R₈, R₃₁ andR₃₂ in formula (5), and R₁ to R₈, R₃₁ and R₃₂ and R₁′ to R₈′, R₃₁′ andR₃₂′ may be the same or different.
 5. A process for synthesizing aperylene derivative according to claim 1 wherein the coupling reactionis homo- or hetero-coupling reaction using a catalyst.
 6. A process forsynthesizing a perylene derivative according to claim 5 wherein thecatalyst is a metal catalyst, metal complex catalyst or metal compound(exclusive of metallic copper) containing at least one element selectedfrom among the Group VIII elements of Ni, Pd, Pt, Fe, Co, Ru and Rh, andthe Group IB elements.
 7. A process for synthesizing a perylenederivative according to claim 5 wherein said catalyst is NiCl₂(dppe),NiCl₂(dppp) or Ni(COD)₂.
 8. A process for synthesizing a perylenederivative according to claim 1, including the steps of using a1,8-dihalogenated naphthalene derivative of formula (1) as set forth inclaim 2 and a naphthyl-1,8-diboronic acid derivative of the followingformula (7):

wherein Z is a boronic acid derivative, and R₁ to R₄, R₁₁ and R₁₂ are asdefined in formula (1), and subjecting them to Suzuki coupling reaction,thereby synthesizing a perylene derivative of formula (2).
 9. A processfor synthesizing a perylene derivative according to claim 1, includingthe steps of using a 3,4-dihalogenated fluoranthene derivative offormula (3) as set forth in claim 3 and a fluorantheno-1,8-diboronicacid derivative of the following formula (8):

wherein Z is a boronic acid derivative, and R₁ to R₆, R₂₁ and R₂₂ are asdefined in formula (3), and subjecting them to Suzuki coupling reaction,thereby synthesizing a perylene derivative of formula (4).
 10. A processfor synthesizing a perylene derivative according to claim 1, includingthe steps of using a 3,4-dihalogenated benzofluoranthene derivative offormula (5) as set forth in claim 4 and adibenzofluorantheno-1,8-diboronic acid derivative of the followingformula (9):

wherein Z is a boronic acid derivative, and R₁ to R₈, R₃₁ and R₃₂ are asdefined in formula (5), and subjecting them to Suzuki coupling reaction,thereby synthesizing a perylene derivative of formula (6).
 11. A processfor synthesizing a perylene derivative according to claim 1, includingthe steps of using a naphthalene derivative of the following formula(13):

wherein X is Cl, Br or I, Z is a boronic acid derivative, and R₁ to R₄,R₁₁ and R₁₂ are as defined in formula (1), and subjecting it to Suzukicoupling reaction, thereby synthesizing a perylene derivative.
 12. Aperylene derivative synthesizing process comprising the steps of using afluoranthene derivative of the following formula (14):

wherein X is Cl, Br or I, Z is a boronic acid derivative, and R₁ to R₆,R₂₁ and R₂₂ are as defined in formula (3), and subjecting it to Suzukicoupling reaction, thereby synthesizing a perylene derivative.
 13. Aperylene derivative synthesizing process comprising the steps of using abenzofluoranthene derivative of the following formula (15):

wherein X is Cl, Br or I, Z is a boronic acid derivative, and R₁ to R₈,R₃₁ and R₃₂ are as defined in formula (5), and subjecting it to Suzukicoupling reaction, thereby synthesizing a perylene derivative.
 14. Aperylene derivative synthesizing process wherein at least one derivativeselected from among 1,8-dihalogenated naphthalene derivatives of formula(1) as set forth in claim 2, 3,4-dihalogenated fluoranthene derivativesof formula (3), and 3,4-dihalogenated benzofluoranthene derivatives offormula (5) is used to form an asymmetric compound.
 15. A perylenederivative synthesizing process according to claim 14 wherein saidasymmetric compound is a compound of the following formula (10):

wherein R₅₁ to R₅₅, R₆₁ to R₆₅, R₁₁₁ and R₁₂₁ are as defined for R₁ toR₄, R₁₁ and R₁₂ in formula (1).
 16. A perylene derivative synthesizingprocess according to claim 1 wherein said perylene derivative is acompound of the following formula (11):

wherein R₁₁₁, R₁₂₁, R₁₁₁′ and R₁₂₁′ are as defined for R₁ to R₄, R₁₁ andR₁₂ in formula (1).
 17. A perylene derivative synthesizing processaccording to claim 1 wherein said perylene derivative is a compound ofthe following formula (12):

wherein R₁₁₁, R₁₂₁, R₁₁₁′ and R₁₂₁′ are as defined for R₁ to R₄, R₁₁ andR₁₂ in formula (1).
 18. A perylene derivative synthesizing processaccording to claim 4 wherein at least R₅ and R₆ and/or R₅′ and R₆′ aredifferent.
 19. A process for synthesizing a perylene derivativeaccording to claim 1 wherein a bisnaphthalene derivative of thefollowing formula (16):

wherein X is Cl, Br or I, R₁ to R₄, R₁₁ and R₁₂ each are a hydrogenatom, a straight, branched or cyclic alkyl radical which may besubstituted, a straight, branched or cyclic alkoxy radical which may besubstituted, a straight, branched or cyclic alkylthio radical which maybe substituted, a straight, branched or cyclic alkenyl radical which maybe substituted, a straight, branched or cyclic alkenyloxy radical whichmay be substituted, a straight, branched or cyclic alkenylthio radicalwhich may be substituted, a substituted or unsubstituted aralkylradical, a substituted or unsubstituted aralkyloxy radical, asubstituted or unsubstituted aralkylthio radical, a substituted orunsubstituted aryl radical, a substituted or unsubstituted aryloxyradical, a substituted or unsubstituted arylthio radical, a substitutedor unsubstituted amino radical, a cyano radical, a hydroxyl radical, a—COOM₁ radical (wherein M₁ is a hydrogen atom, a straight, branched orcyclic alkyl radical which may be substituted, a straight, branched orcyclic alkenyl radical which may be substituted, a substituted orunsubstituted aralkyl radical, or a substituted or unsubstituted arylradical), a —COM₂ radical (wherein M₂ is a hydrogen atom, a straight,branched or cyclic alkyl radical which may be substituted, a straight,branched or cyclic alkenyl radical which may be substituted, asubstituted or unsubstituted aralkyl radical, a substituted orunsubstituted aryl radical, or an amino radical), or a —OCOM₃ radical(wherein M₃ is a straight, branched or cyclic alkyl radical which may besubstituted, a straight, branched or cyclic alkenyl radical which may besubstituted, a substituted or unsubstituted aralkyl radical, or asubstituted or unsubstituted aryl radical), and at least two adjoiningradicals selected from among R₁ to R₄, R₁₁ and R₁₂ may bond or fusetogether to form a substituted or unsubstituted carbocyclic aliphaticring, aromatic ring or fused aromatic ring with the carbon atoms onwhich they substitute, with the proviso that when the carbocyclicaliphatic ring, aromatic ring or fused aromatic ring has substituentradicals, the substituent radicals are the same as R₁ to R₄, R₁₁ andR₁₂, is subjected to coupling reaction to synthesize a perylenederivative of the following formula (2):

wherein R₁′ to R₄′, R₁₁′ and R₁₂′ are as defined for R₁ to R₄, R₁₁ andR₁₂ in formula (1), and R₁ to R₄, R₁₁ and R₁₂ and R₁′ to R₄′, R₁₁′ andR₁₂′ may be the same or different.
 20. An organic EL device comprisingthe perylene derivative obtained by the process of claim
 1. 21. Anorganic EL device according to claim 20 wherein the perylene derivativeis contained in a light emitting layer.
 22. A perylene derivative havinga structure of the following formula (10):

wherein R₅₁ to R₅₅, R₆₁ to R₆₅, R₁₁₁ and R₁₂₁ are as defined for R₁ toR₄, R₁₁ and R₁₂ in formula (1).